Genomics and Cell Biology: December 2009

NASA astrobiologists studying the origin of life have reproduced uracil, a key component of RNA, in the laboratory. They discovered that an ice sample containing pyrimidines exposed to ultraviolet radiation under space-like conditions produces this essential ingredient of life. The study appears in the September issue of Astrobiology.

"We have demonstrated for the first time that we can make uracil, a component of RNA, non-biologically in a laboratory under conditions found in space," said Michel Nuevo, research scientist at NASA's Ames Research Center. "We are showing that these laboratory processes, which simulate occurrences in outer space, can make a fundamental building block used by living organisms on Earth."

Abstract: Ribosomes are RNA-based macromolecular machines responsible for the synthesis of all proteins in all living organisms. Ribosomes are the most ancient of life's macromolecules and are our most direct link to the deep evolutionary past, beyond the base of the phyologenetic tree. The recent availability of high resolution 3D structures of ribosomes provides us with new methods of detection and inference. We will discuss methods for resurrection and biochemical characterization of aboriginal ribosomes.

Appearing in the Nov. 27, 2009, issue (Vol. 284, No. 48) of JBC: A key question in the origin of biological molecules like RNA and DNA is how they first came together billions of years ago from simple precursors. Now, in a study appearing in this week's JBC, researchers in Italy have reconstructed one of the earliest evolutionary steps yet: generating long chains of RNA from individual subunits using nothing but warm water.

Many researchers believe that RNA was one of the first biological molecules present, before DNA and proteins; however, there has been little success in recreating the formation on RNA from simple "prebiotic" molecules that likely were present on primordial earth billions of years ago.
Now, Ernesto Di Mauro and colleagues found that ancient molecules called cyclic nucleotides can merge together in water and form polymers over 100 nucleotides long in water ranging from 40-90 *C -similar to water temperatures on ancient Earth.